This invention relates to a method and apparatus for manufacturing a laminated prepreg member or article by laminating prepreg layers prepared by impregnating setting or thermoplastic resin into reinforced fibers, and more particularly, a method and apparatus for efficiently and automatically manufacturing a laminated prepreg member by using the same operating table.
A prepreg is a type of moldable material used for making reinforced plastics and is prepared by uniformly impregnating a thermosetting resin prepared by admixing a curing agent, a coloring agent, and a filler at a suitable ratio into such reinforcing member as a glass mat or a glass cloth. After impregnating, the prepreg is dried to semi-set or cured state so that the resulting prepreg member is pliable. When using the prepreg member to form parts of motor cars, aeroplanes, motor boats, etc. the prepreg member is coated on a mold of the part coated with a mold release agent. After the prepreg member has been perfectly set or cured under pressure and heat, the completed product is hard and light and has a strength larger than that of steel sheet. For this reason, in recent years prepreg products are abundantly used in various vehicles.
Heretobefore, sport or leisure merchandise, and structural parts of various machines have been made of such composite materials as carbon fibers reinforced with plastic (CFRP) or the like. Such composite materials have been prepared by impregnating thermosetting or thermoplastic resin into carbon fibers, aramid fibers, boron fibers, glass fibers or other reinforcing fibers to prepare a prepreg layer. Then the prepreg layers are laminated at different angles to obtain a laminated prepreg sheet. The laminated prepreg sheet is cut to have a shape suitable for parts to be prepared. A cut piece of a laminated prepreg sheet is mounted on a shaping jig and then applied with heat and pressure to be molded into an article having a desired configuration and strength.
In the past, a laminated prepreg member has been prepared by forming a laminated prepreg sheet by using a prepreg laminating apparatus and then conveying the sheet to a trimming machine for cutting the sheet to have a desired configuration. For efficiently laminating the prepreg sheets, a flexible tape (hereinafter called as a backing paper) having one surface impregnated with a silicone is prepared and then the prepreg sheet is bonded to the other surface to obtain a prepreg tape. In the prepreg laminating apparatus, the prepreg layer is peeled off from the prepreg tape and the layer is continuously oriented in a predetermined direction, and then laminated while applying a pressure to obtain a prepreg sheet. Furthermore, for identifying individual laminated prepreg members, a marking device is used for applying an identification mark onto a portion of each laminated prepreg member.
In the foregoing method and apparatus for preparing laminated prepreg member, respective manufacturing steps have been carried out discontinuously at different places. Moreover, it has been necessary to convey laminated prepreg sheets to different places at which respective steps are carried out. For this reason, there are the following problems:
(a) when a thermosetting type prepreg tape and a laminated prepreg member are maintained at a room temperature, the chemical reaction proceeds to harden the material. For this reason, where it is necessary to temporarily interrupt the molding operation at an intermediate point of adjacent steps, it is necessary to temporarily store the laminated prepreg member in a refrigerating cabinet maintained at a temperature of below about -18.degree. C. This necessitates a useless operation and much operating time.
(b) Since not cured prepreg and laminated prepreg member are soft and flexible their handling and conveyance are difficult. For this reason, it is necessary to use a special jig for conveying the laminated prepreg member. Thus, the conveying operation is not only troublesome but also requires a long operating time.
(c) Since treating times at various steps are different, even when the steps are automated, it is impossible to realize a line balance between respective steps, thereby decreasing the actual operating time of the apparatus as a whole.
(d) Where machining operation or manual operation is necessary at respective steps, it is necessary to prepare a manufacturing program for each step and to prepare a working program. Thus, the supervision of manufacturing becomes troublesome and not efficient.
(e) Where the laminating operation of the prepreg piece and the cutting operation of the laminated prepreg sheet are made on different operating tables, at least two operating tables are necessary, thus increasing the installation space of the manufacturing apparatus.
(f) Where a prepreg sheet is formed by peeling off a desired portion from a prepreg tape, the sheet has been formed while the prepreg tape is being cut. Accordingly, it has been impossible to laminate the prepreg tape during the cutting thereof, whereby a long time is necessary for laminating the prepreg sheets.